A few examples will help to illustrate how you might use the databases in the Invisible Web. Let’s say you’re trying to find out all the movies that Brad Pitt and Kevin Bacon starred in together. If you went to the Internet Movie Database to perform this search, the data you would retrieve would not be accessible via a search engine. Now, that's not to say that the only way to find out that these two actors starred together in "Sleepers" is to search the IMDb. It’s entirely possible that after some time spent searching the Web using various general search tools and browsing biography sites on the two actors you may very well find this information. But it is to say that the only way to access the data contained in the IMDb - which is the most efficient and quickest way to find this specific type of movie information - is to perform a search directly at the IMDb using the search box. A search engine won't bring up this information for you, since the "answer" was created dynamically as you performed the specific search in the IMDb.
Similarly, suppose your boss asks you to find out how many non-fatal plane crashes Virgin Airlines has had in the last five years. Browsing the Web using general search tools will not be a great way to find this data. But if you go to the Aviation Accident Database and perform a search there, you will retrieve exactly what you need very quickly. And the data on the three non-fatal crashes that this database finds for you is not easily (or not at all) found on the Web by using general search engines.
Just knowing that these databases are out there, and knowing in which situations you should use them, is a great start to becoming a more thorough searcher. The next time you get a specific movie industry question or an airline crash question you’ll know how to get your answer efficiently. There are many, many databases that comprise the Invisible Web, and Gary Price has put together a fantastic list of them at Direct Search. For further reading, have a look at a great overview of this topic by Chris Sherman of About.com in his article The Invisible Web. Other great resources are the Berkeley Teaching Library's Invisible Web Tutorial page (put together by Joe Barker), IntelliSeek's The Invisible Web, and CompletePlanet.
